The skin is the largest organ, constitutes one of the largest surface areas, and accounts for about 15 percent of the entire weight of the human body. The skin is composed of several layers, the two main layers of which are the epidermis and dermis. The dermis lies below the epidermis and is comprised of loose connective tissues such as collagen, elastin and reticular fibers. The dermis includes a number of pores and structures such as blood vessels, nerves, hair, follicles, smooth muscles, glands and lymphatic tissues. Removing the top layers of the dermis promotes regeneration of collagen, elastine, and epidermis. This can rejuvenate the facial skin long term, and improve the appearance of fine line and wrinkles. Skin resurfacing can also remove superficial blemishes such as the brown spots of ageing, dilated capillaries, and small keratoses.
One procedure currently in wide use for skin resurfacing involves exposure to a laser, usually one that employs nonablative laser technology. Because any given laser emits light of only one wavelength (or color), they work in cosmetic applications through a process called selective photothermolysis. To be effective, the wavelength of the light beam must be in sync with the color of the target which is to be addressed, whether that be brown spots, unsightly red broken capillaries or some other undesirable skin condition. The most-commonly used lasers for the treatment of pigmented lesions, such as sun spots, age spots melasma and other forms of hyperpigmentation are the pulsed dye, Nd:YAG and fractional (Fraxel) lasers, along with nonlaser, light-based treatments, such as IPL.
Lasers useful in cosmetic procedures also include CO2 (carbon dioxide) laser or Erbium YAG for treating lines and wrinkles, the removal of warts and skin tags, acne scars and for cutting skin in laser-assisted surgery. Pulsed Dye Lasers have also shown some success, along with less aggressive nonlaser, light-based treatments, such as intense pulsed light (IPL) and LED photofacials. Most cosmetic laser procedures provide some level of superficial tightening because they produce a controlled injury of the skin, which encourages increased collagen production. For more significant tightening results CO2 lasers or nonlaser, light-based treatments, such as Titan infrared devices and Thermage radio-frequency based systems may be used.
Resurfacing methods also include chemical peeling and dermabrasion. A chemical peel causes a chemical burn. Dermabrasion mechanically removes the epidermis and a variable layer of dermis. Recently, a rapid scanning device has been added to the cutting laser, enabling a predictable depth of skin to be destroyed. Resurfacing methods treat superficial wrinkles and repair skin aged by light.
Despite the large numbers of such procedures, there remains a need for materials, methods and systems for treating and dressing post-procedure skin. It is desirable to accelerate the healing and to restore the functional barrier property of the skin as rapidly as possible, preferably with a cosmetically acceptable formulation. Skin resurfacing procedures result in predictable post-operative sequelae including facial edema, wound exudate and erythema. In addition, there may be pain, pruritis, hyperpigmentation, milia formation and acne. It is desirable to address all of these consequences of wounding and aspects of healing.